<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <button>点击停止定时器</button>
    <script>
        var btn = document.querySelector('button');
        // 设置定时器
        var timer = setTimeout(function(){
            console.log('爆炸了');
        },5000);
        // 清除定时器 clearTimeout(timer); clearTimeout 清除定时器 timer 定时器名字
        btn.addEventListener('click',function(){
            clearTimeout(timer);
        });
    </script>
</body>
</html>